1. Field of the Invention
This invention relates to fiber optics and has particular reference to improvements in arrays of tapered optical fibers.
2. Discussion of the Prior Art
For the purpose of carrying light from a closely spaced array of light sources or illuminated image elements to a relatively widely separated array, assemblies of monofibers have a definite functional advantage over the easier to manufacture assemblies of conventional tapered fibers; namely, the small size of the exit core which prevents overlapping or intermixing of light or image elements in the separated array and/or waste of emitted light by excessive spreading. Countering this advantage, however, are the difficulties, tediousness and costliness involved in arranging and supporting numbers of monofibers with their corresponding one end tightly juxtapositioned and opposite ends spaced apart. Tapered fibers, on the other hand, which can be readily and efficiently joined into tightly juxtapositioned relationship throughout their lenths for avoidance of the aforesaid manufacturing problems, produce relatively inefficient and/or inferior devices.
While predetermined different spacings between centers of corresponding opposite ends of fibers in conventional tapered arrays may be provided by selection of the taper ratio of the fibers or array, the large size of light exit core of each fiber, i.e. at the large end of the taper, causes the aforesaid adverse overlapping or intermixing of light or image elements and waste of emitted light by excessive spreading.
Accordingly, the hitherto need to make a choice between ungainly assemblies of monofibers with their difficulties and costliness of manufacture and conventional more compact and easily manufactured multifiber tapers with their drawbacks of relatively inefficient light or image element emission has, heretofore, left much to be desired in the art.
With a view to overcoming the aforesaid and corollary drawbacks or disadvantages of prior art fiber optic image-expanding or image-element-separating systems, the present invention provides the improvement in a tapered fiber optic array wherewith the taper ratio of the array as a whole can be selected to provide the desired image element spacing along with simultaneous control of numerical aperture.